Want to lower your energy bill? You might think it requires covering your roof with solar panels, erecting a backyard wind turbine, or installing a new air conditioning system. But simpler and less-expensive strategies make a major dent, too.

Window film is one such home improvement. Properly applied, window film can cut your household cooling costs by almost one-third.

That’s a big deal in Florida, where the U.S. Energy Information Administration (EIA) estimates we spend 40 percent more than the rest of country on electric bills. A big part of that difference: Floridians use a lot of air conditioning — four times the national average. The EIA found that 27 percent of the energy used in Florida homes goes to air conditioning.

Window Film Can Lower A/C Costs

According to Darrell Smith, executive director of the International Window Film Association, window film makes a lot of sense for homeowners eager to save money on their power bills.

“Solar-control films can block as much as 80 percent of the solar heat coming through glass into a building, decrease the heat load on the air-conditioning system, and reduce energy costs,” Smith says. He estimates that professionally installed window film can cut those costs by up to 30 percent.

“The great aspect of most window films is that they aid in blocking up to 99 percent of harmful UV rays, which reduces solar heat gain,” says Dave Mayer, OUC Sustainability Supervisor. “By controlling the direct sunlight that enters the home, it improves comfort and maintains temperature consistency in the home.”

Window film not only saves energy, it can keep what’s in your home from suffering the ravages of ultraviolet light, which can cause carpets, furnishings, fabrics and artwork to fade or discolor. Smith estimates that 40 to 60 percent of color fading is caused by UV exposure.

How Does Window Film Work?

In homes, film is usually applied to the interior surface of the window. The film can be almost completely clear, or darker to reduce glare and provide extra privacy. Some films even feature patterns and designs — and a few even mimic stained glass.

Although window film is a passive, low-maintenance, energy-saving project, the product itself is by no means low-tech. The film consists of from six to 14 layers of polyester that have been treated chemically or with a metallic deposition process. The finished film is 1½ mils thick — that’s 1½ thousandths of an inch. “It’s complex to manufacture,” Smith says. “The thought that it’s just a sheet of shiny plastic is not true.”

Window Film Isn’t New

Window film first entered the consumer market as a luxury add-on for cars, trucks and vans in the late 1970s. Then it worked its way into commercial buildings, where its familiar reflective sheen graced many skyscrapers.

In the 1980s, the automotive market really took off when the Sun Belt’s booming population bought window film to cut glare and keep car interiors cooler. From there, window film quickly established itself in homes. Today, the product meets the demand of cost-conscious owners looking for energy-efficient, green solutions, Smith says.

Should You Install Window Film Yourself or Hire Someone?

One final piece of advice about installing window film – you’re probably better off leaving the job to a pro. Just remember the frustration you experienced when you tried to apply a dust-and air-bubble free protective film to your smartphone or tablet. Now imagine trying to do the same thing to a surface the size of a pool table.

“If someone is very good at installing wallpaper, they could be good at installing window film,” Smith says. Everyone else should rely on a professional.

Mayer recommends that homeowners have film installed on windows that face east, west and south. OUC offers rebates to customers if the shading coefficient of the film is 0.5 or less. (The shading coefficient is the measure by which shading materials are rated.)

“The lower the coefficient, the better it is for providing more shade in a room,” Mayer says.